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/*! \file
  \brief Epilogue for threadblock scoped GEMMs using WMMA.

  The epilogue rearranges the result of a matrix product through shared memory
  to match canonical tensor layouts in global memory. Epilogues support
  conversion and reduction operations.

*/

#pragma once

#include "cutlass/cutlass.h"
#include "cutlass/numeric_types.h"
#include "cutlass/array.h"

#include "cutlass/gemm/gemm.h"

#include "cutlass/epilogue/thread/linear_combination.h"
#include "cutlass/epilogue/thread/linear_combination_clamp.h"
#include "cutlass/epilogue/thread/conversion_op.h"
#include "cutlass/epilogue/thread/reduction_op.h"

#include "cutlass/transform/threadblock/regular_tile_iterator_pitch_linear.h"

#include "cutlass/epilogue/warp/fragment_iterator_wmma_tensor_op.h"
#include "cutlass/epilogue/warp/tile_iterator_wmma_tensor_op.h"
#include "cutlass/epilogue/threadblock/default_thread_map_wmma_tensor_op.h"
#include "cutlass/epilogue/threadblock/predicated_tile_iterator.h"
#include "cutlass/epilogue/threadblock/shared_load_iterator.h"

#include "cutlass/epilogue/threadblock/epilogue.h"

////////////////////////////////////////////////////////////////////////////////

namespace cutlass {
namespace epilogue {
namespace threadblock {

////////////////////////////////////////////////////////////////////////////////

/// Defines sensible defaults for epilogues for WMMA TensorOps.
template <typename Shape_, typename WarpMmaTensorOp_, int PartitionsK,
          typename OutputOp_, int ElementsPerAccess>
struct DefaultEpilogueWmmaTensorOp {
    using Shape = Shape_;
    using WarpMmaTensorOp = WarpMmaTensorOp_;
    static int const kPartitionsK = PartitionsK;
    using OutputOp = OutputOp_;
    static int const kElementsPerAccess = ElementsPerAccess;

    using ElementOutput = typename OutputOp::ElementOutput;
    using LayoutC = typename WarpMmaTensorOp::LayoutC;
    using ElementAccumulator = typename WarpMmaTensorOp::ElementC;

    //
    // Thread map
    //

    using OutputTileThreadMap = typename cutlass::epilogue::threadblock::
            DefaultThreadMapWmmaTensorOp<
                    Shape, typename WarpMmaTensorOp::Shape,
                    typename WarpMmaTensorOp::Policy::Operator::Shape,
                    kPartitionsK, ElementOutput, kElementsPerAccess>::Type;

    using OutputTileIterator =
            cutlass::epilogue::threadblock::PredicatedTileIterator<
                    OutputTileThreadMap, ElementOutput>;

    using AccumulatorFragmentIterator =
            cutlass::epilogue::warp::FragmentIteratorWmmaTensorOp<
                    typename WarpMmaTensorOp::Shape,
                    typename WarpMmaTensorOp::Policy::Operator::Shape,
                    typename WarpMmaTensorOp::Policy::Operator::ElementC,
                    typename WarpMmaTensorOp::Policy::Operator::FragmentC,
                    LayoutC>;

    using WarpTileIterator = cutlass::epilogue::warp::TileIteratorWmmaTensorOp<
            typename WarpMmaTensorOp::Shape,
            typename WarpMmaTensorOp::Policy::Operator::Shape,
            typename WarpMmaTensorOp::Policy::Operator::FragmentC, LayoutC>;

    using SharedLoadIterator =
            cutlass::epilogue::threadblock::SharedLoadIterator<
                    typename OutputTileThreadMap::CompactedThreadMap,
                    ElementAccumulator>;

    /// Hard-coded padding elements added
    using Padding = typename WarpTileIterator::Padding;

    //
    // Define the epilogue
    //
    using Epilogue = cutlass::epilogue::threadblock::Epilogue<
            Shape, WarpMmaTensorOp, kPartitionsK, OutputTileIterator,
            AccumulatorFragmentIterator, WarpTileIterator, SharedLoadIterator,
            OutputOp, Padding>;
};

////////////////////////////////////////////////////////////////////////////////

}  // namespace threadblock
}  // namespace epilogue
}  // namespace cutlass

////////////////////////////////////////////////////////////////////////////////
